Side effect of replacing a table with a view

I'm looking for input on what possible negative side effects I could
encounter, if I replace a table with a view.

Situation:

I need to add a few columns to an existing, non-partitioned, heap table
(let's call it "a"). However, I have identified a large number of "select *
" queries against this table. Finding where these queries are coming from
and changing them is not feasible within the current environment.

So, I'm basically looking at two alternatives:

rename the existing table to "b", add the new columns to it and
create a view named "a". The view will not expose any of the new columns

create another table "a_ext", with the same PK as "a", enforce RI
(cascade delete), add the new columns to it. Also add an update trigger on
"a", in case the PK in "a" gets updated, so that the PK in "a_ext" gets
updated too.

I prefer #1, but I'm concerned about possible negative side effect of
renaming the table. Let's not worry about downtime, since it's not an issue
in this environment. However, since table "a" is a very critical table, we
need to make sure we do not break any existing code.

We use Oracle 8.1.7.0, and yes it is .0, not .4

Question:

Are there any operations that could fail as the result of replacing the
table with a view?